Bag and container for heavy duty



W. W. ROWE Feb. 23, 1937.

BAG AND CONTAINER FOR HEAVY DUTY Filedy April 4, 1935IIIIIIIIIIIIIIIIIIL fav:

- INVENTOR.

ATTORNEY.

Patented Feb. 23, 1937 UNITED STATES PATENT GFFICE William Wallace Rowe,Cincinnati, Ohio, assigner.

to The Paper Service Company, Lockland, Ohio,

a. corporation of Ohio Application April 4, 1933, Serial No. 664,377

16 Claims.

My invention relates to bags or other flexible containers of novelcharacteristics and materials. By heavy duty I refer to containerscapable of carrying 50 to 100 pounds or more of contents; but it will beunderstood that the size and Weight carrying capacity of my containersdo not constitute limitations upon my invention. Heretofore heavy dutybags have been made of multiple walls of plain paper or of textilematerial, such as burlap, sometimes with an inner liner, or of compositefabrics comprising textile material cemented to creped paper. In themulti-Wall paper bag, the object has been to add together enough pliesof paper so that the ultimate strength of the sum of these plies will begreater than the shocks to which it is expected the bag will besubjected. The plies were left free of each other, because it would beimpracticable to cement them together in a solid fabric. Such a solidlycemented fabric would be inflexible and would crack upon bending. Again,in bags of textile material or composite materials, it has been theendeavor to provide a bag wall of sufficient ultimate strength towithstand the expected shocks.

It is an object of my invention to provide a more serviceable container,and more particularly a container adapted to withstand individual orsuccessive shocks in a superior way. It is an object of my invention toprovide a container which can withstand a series of shocks greater thanthe ultimate strength of the materials of which the container is made.It is a further object to provide a container in which resistance toshocks and strains is a function of the elasticity of the materials ofthe container, rather than of their ultimate tensile strength, i. e. acontainer in which strength is secured through stretchability. Stillanother object of my invention is the provision of containers which havegreater serviceability though made of cheaper materials. Still anotherobject of my invention is the provision of containers of paper materialswhich nevertheless can withstand a greater succession of shocks thancontainers heretofore made of multi-wall paper, or of textile materialsas the primary strengthening element, the fabric of which is of the sameor even greater weight per square unit of area than the webs in mycontainer. Still another object of my invention is the solution of theproblems involved in seam formation in containers, and more particularlythe elimination of desiderata heretofore considered essential in theformation of cemented seams in containers.

Another object of my invention is the provision of a container madeprimarily of paper in a single or in a plurality of plies, and in which,if a l plurality of plies are employed, the plies may be cementedtogether with attendant advantage, and without loss of adequateflexibility and stretchability.

These and other objects of my invention, which will be set forthhereinafter or will be apparent to one skilled in the art upon readingthese specifications, I accomplish by that certain construction andarrangement of parts of `which I shall now describe certain exemplaryembodiments, reference being had to the drawing, wherein:

` Figure 1 is a plan view of one bag which may be made in accordancewith my invention, with the original bag blank indicated in dottedlines.

Figure 2 is a somewhat exaggerated and diagrammatic section of the bagof Figure 1, taken along the lines 2 2.

Figure 3 is a plan view of another exemplary 20 form of bag.

Figure 4 is a sectional view of the bag of Figure 3, again exaggeratedand semi-diagrammatic, taken along the lines 3--3 in Figure 3.

Figure 5 illustrates the effect of repeated end 25 drops upon a bag ofmy invention.

Fig. 6 is a sectional view, somewhat diagrammatic in form, of theexemplary fabric which I may employ in carrying out my invention.

Briefly in the practice of my invention I form i a bag or container of amaterial which is simultaneously expansible in all directions, so thatthe strains set up by rough handling, as in the dropping of the bag whenloaded, will be absorbed in the resultant expansion. I believe this tobe a complete novelty in the construction of containers and bags of theclass to which my invention is addressed. I have found that in thepractice of my invention the ultimate bursting strength of thematerials, while high, is nevertheless not a factor in theirserviceability unless and until the whole resident expansibility of thestrained area throughout the bag is destroyed; and the tearing strengthof the materials, while also high, is not a factor in theirserviceability until the bag wall has been punctured.

In cloth bags, or bags which are combinations of cloth and paper, whilethere is a possible distortion along the bias, this distortion orstretchability occurs at the expense of contraction else- Where, andthere is substantially no stretchability transversely or longitudinallyof the fabric. Thus, substantially the entire strain of an end drop on afilled bag is applied against the ultimate bursting strength of thestructure. In bags having seams held by sewing alone, there are factorswhich tend to cause the rupture to occur in the seam. Seams can be madewhich are stronger than the materials themselves; but then the entirestress is applied against the ultimate bursting strength of the fabric.

In a multiple wall paper bag, since there is no stretchability in theseveral plies, the stresses are immediately effective against theultimate strength of the material which, therefore, in the aggregate hasto be very heavy.

In my novel structure the stresses so produced are relieved by anexpansion of the fabric itself. The fabric is preferably one in whichexpansion is resisted within the ultimate strength limits, and it may beone in which there is a strong resilience, or tendency of the materialto return to its original unexpanded form. It will be obvious, however,when the character of stresses to which bags are subjected isconsidered, that the stretchability to be serviceable to my end, must bea universal stretchability and not merely a unilateral stretchability,or a stretchability limited to a few specific directions. But it willalso be apparent that the stretchability to which I refer is effectiveagainst localized as well as general stresses, for which reason mystructures are very resistant to puncturing. Not only this, but so longas there is suflicient universal stretchability to absorb the stressesaforesaid the seam is likewise protected from strain, and there is nonecessity for a seam construction which itself is elastic. Thus, whilemy invention is not limited as to seam construction, I may employ a verymuch simpler seam than has heretofore been found necessary.

In a co-pending application Serial No. 668,106, filed April 26, 1933, Ihave set forth a fabric comprising a plurality of plies of universallystretchable creped paper. The plies themselves are preferably made inaccordance with the teachings of the co-pending application of WilliamC. Kemp, Serial No. 558,884, filed Aug. 24, 1931, which teaches aprocess of creping paper and a product which is the result of thatprocess, and which comprises paper having a plurality of crossing setsof diagonally disposed creping crinkles. The paper is a true crepedpaper as dstinguished from a corrugated paper or a paper having suchlarge or irregular rugosities as would prevent a fairly continuous bondto another web in making up a plural ply fabric. My invention, however,is not limited to this particular type of universally stretchablefabric.

Two or more layers of this universally stretchable paper are joinedtogether by a suitable adhesive to make a plural ply fabric. Theadhesive used for the purpose may be, if desired, the thermoplasticadhesive employed in the creping operation, such, for example, asasphalt, or it may be an additional adhesive, or, if no thermoplasticadhesive substance has been used in the creping operation, it may be asuperadded adhesive substance. I have set forth in my copendingapplication referred to, a plural ply fabric of this character joined bymeans of asphalt, and also a modification in which stretchability isadditionally resisted by certain types of reinforcements in the adhesivejoining the plies, such as heterogeneously arranged and relatively shortfibers.

This particular fabric which is exemplary only of those I may use, isillustrated in Fig. 6, where three layers of double diagonally crepedpaper I8, I9, and 20, are shown joined together by layers of asphalticsubstance 2l and 22.

In another co-pending application Serial No. 668,105, filed April 26,1933, I have set forth a plural ply fabric in which a resilient andelastic coating substance is an integral part, Whether employed as themeans for building up the plural ply fabric, or not. Any of thesematerials may be employed by me in my present invention which, as to thefabric, is not limited otherwise than to a single ply of universallystretchable paper or like material, or to a plurality of layers ofuniversally stretchable material.

I have shown in Figure 1 a blank l which, when folded and joined by acenter seam 3, will form the bag body 5. The structure shown isexemplary merely of a type of bag which may be made in accordance withmy invention, and does not otherwise constitute a limitation. A bottomseam 6 may be formed in this particular structure by turning over anintegral body flap 1. Likewise, I have shown a top sealing flap 8 alsohaving integral portions joining it to the opposite body wall andindicated at 9 and I0. After lling this bag, the top flap may be turnedover and cemented in place or otherwise fastened as desired. A sealingmethod of particular advantage in bags of this character is Set forth inmy co-pending application Serial No. 647,000, filed Dec. 13, 1932, andinvolves the coating of parts to be lapped and joined with an uncuredrubbery substance, and protecting this substance from influences whichwould tend to destroy its adhesiveness to bodies of a similar substance.When the protective material has been removed, the parts may merely belapped and pressed together, whereupon the instant adhesion produces astrong bond.

In Figure 2 I have indicated a cross section of the body of the bag ofFigure 1 to show a satisfactory character of seam construction 3, whichcomprises merely the lapping of the parts and the joining of them bymeans of the adhesive Il. Hitherto, in heavy duty bags made of compositematerials it has been thought impracticable merely to lap and join theedges of. the body fabric. Thus, in composite materials of textile andpaper, it has been thought necessary to provide a seam construction inwhich textile material may be cemented directly to textile material bymeans of rubber latex or the like. A seam construction in which thepaper is involved as an integral element has been thought impracticable,because the paper itself is not the main strength giving element of thebag, and also because in the usual forms of construction the paper isjoined to the burlap by an asphaltic layer subject to softening andslippage under the influence of temperature. Likewise, in heavy bags ofuncreped duplex papers, it has been thought necessary to provide astructure for seam formation in which the several plies arenon-coterrninous, and to cement the outer ply directly to the outer ply,and preferably also the inner ply directly to the inner ply by means ofsome adhesive substance other than the bitumen by which the plies arecombined to make the duplex paper.

In the multi-wall bag, on the other hand, in which the several plies ofpaper are free of each other, it is obvious that a single cemented seamintended to be effective for all plies, would be inoperative unless someattempt were made to join all of the plies, as by cementing themtogether, at least over the area of seam formation. Such an attemptwould be uneconornical. Even if the plies were so joined, however, anyslippage of the plies would result in the strain being thrown againstthe outer ply or plies, and a great reduction in seam strength.Moreover, the joining of the several plies would build up a stiff, thickmaterial subject to cracking when bent. All of these disadvantages arisethrough the lack of stretchability in the paper.

In the bag of my invention, plain lapped and cemented seams or buttedjoints with overlying cemented strips and the like are found perfectlysatisfactory from the standpoint of strength and serviceability, andthey also, of course, greatly simplify the construction of seams. Thereasons for the efficacy of such simple seams in my construction Ibelieve to reside primarily in the universal stretchability of the bagfabric itself. So long as there is any resident stretchability in thewalls of the bag, the seam is protected. Likewise, due to the universalstretchability of the body walls of my bag where they are formed ofplural ply materials, there is no tendency for the walls to slip in theseam construction, whereby inordinate strain might be put on the outerply or plies. In cemented constructions of the type refered to, thematerial in the lapped portions is relatively less stretchable than thematerial elsewhere. Consequently, the body walls of the bag Will stretchbefore a slippage will occur in the seam. Hence, since the layers in theseam do not slip, the seam construction retains its unimpaired strength.In this way I have succeeded in making adequate lapped seams in pluralply paper fabrics without the necessity of special constructions.

It will be understood that ordinary machinemade paper has a preponderantgrain direction which makes its tensile strength greater in onedirection than in a direction at right angles thereto. The most severestresses encountered by a bag under conditions of use are burstingstresses transverse to the length of the bag. This is because a bag, ifdropped on end, receives a greater effective stress by reason of thegreater height or head of its contents than if the same bag were droppedon its side or on its edge. As an added factor of safety in my bags, Iprefer to construct them in such a way thatthe grain of the paper istransverse to the length of. the bag, whereby the ultimate strength ofthe bag in the direction of greatest stress is increased, particularlywhen the bag is considerably greater in length than in width.

Since it is characteristic of my structure that the ultimate strength ofthe paper is not a factor so long as the resident stretchability is notwholly removed; it follows that the effective resident stretchability ofthe fabric of my bag, l. e. the percentage of stretch in the paper isthe factor of greatest importance in determining the serviceability ofthe bag. The percentage of effective stretchability in the ydirection ofgreatest strain is therefore far more important than the ultimatestrength of the paper in said direction. Universally stretchable papermaterials may have different percentages of stretchability in differentdirections or may be equally stretchable in all directions. Consequentlywhile my invention is not limited in this respect, I prefer to have thepercentage of stretchability the greatest in the direction of greateststrain which, as hereinabove pointed out, is transverse to the length ofthe bag. With universally stretchable paper having a substantial degreeof stretchability, very satisfactory bags may be made by providing afabric in which the stretchability is equal in every direction; but ifthe fabric employed has markedly superior stretchability in onedirection, I prefer to conof relatively light universally stretchablepaper,v

which will more successfully carry the same Weight of contents, andwhich will withstand a much higher single drop or a greater successionof drops from a given height than bags of greater weight comprisingburlap and paper or made of plural plies of uncreped paper, and this inspite of the fact that the ultimate tearing strengthl and the ultimatebursting strength of my material, when all of the stretch has beenremoved therefrom, may be very much less than that of the burlap aloneor the plural plies of uncreped paper.

My bag will withstand substantially any stress the effect of which isinsufficient to remove all of the stretch in the bag walls in thestrained areas. For this reason the walls of my bag may be bent sharplyand in spite of the tendency to remove some of the stretchability, thewalls will be weakened less than would be the case with uncreped paperor single creped paper bent along transverse to the direction of thecreping. Even this however, may be overcome by reinforcing the sideedges of the bag by the use of additional strips of material orotherwise; and since the resident stretchability of the remainder of thebag walls protects these reinforcing con,- structions as well as theseams, no provision for stretchability or elasticity, While desirable,is essential in such reinforcements. I have also overcome the difllcultyin the bag of Figure 3. by forming seam constructions at the side edgesof the bag. The walls of the bag of Figure 3, shown in section in Figure4, are indicated at I2 and I3. At the side edges these Walls arecoterminous, and strips of material I4 and I5 are bound thereabout.'I'he material in these strips may be, if desired, the same as that ofthe bag walls, or they may be of other or ultimately stronger materials,such as textile fabrics or combinations of textile fabrics and paper. Inany event, however, the thickness of the edges of the body walls of thebag protects the material of the seam from undue compression. It will benoted that the bag of Figure 3 is square in shape. I have found thatsuch a bag form evens up the stresses and tends to give a structure ofeven greater serviceability.

I have hereinabove indicated that my bag will preferably be formed ofplies of universally stretchable material cemented together with asubstance which tends to resist the removal of stretch within the limitsof the ultimate strength of the plies. I have likewise indicated thatthe bag may be formed of one or a plurality of plies of universallystretchable material combined with or having in association a materialwhich tends resilientlv to resist the removal of stretch and to returnthe fabric more or less to its original unstretched condition after thealleviation of the stress. Materials having an external coating ofrubbery material may likewise be used to advantage ln my presentinvention, both because of the increased imperviousn'ess of suchfabrics,

and also because the external covering of rubbery material gives them aso-called non-skid quality facilitating the stacking of the bags.

Assuming that the plies are joined by asphalt or the like which merelyresists the removal of stretch, the result of repeated strains upon abag of my invention is illustrated in Figure 5. This condition isbrought about, for example, after the b ag has been loadedl with say 100pounds of material, and has been repeatedly dropped on its end from aheight of say two feet. After manyrepeated drops, the condition of mybag may be as shown, with the lower portions of the side walls balloonedout as indicated at IB and I1. This represents. oi course, anexaggerated condition, and one seldom encountered in the actualcommercial use of the bag. Yet the bag is still intact, and will beuntil subjected to sufficient stress to remove all of the residentstretch and to subject the plies in their unstretchable condition to aforce greater than their ultimate bursting strength. In the bag of myinvention, I have also found that as the stretch is removed from the bagwalls, the so-called spill room is increased, which is a factor tendingto alleviate further stresses. If a bag of textile material or ofcombinations of textile and paper is filled full and closed so as tocause the walls to bear tightly against the contents, a very muchsmaller stress will be required to burst the bag. 'I'his is because theentire stress is immediately applied against the ultimate strength ofthe material. Bags filled less full can withstand a pro- -portionatelygreater amount of stress, because of the so-called spill room. In mybag. spill room increases With stress, either temporarily orpermanently, and the effective serviceability of the bag is therebygreatly increased. Thus, the bags of my invention in filling may bestuifed tightly, and will be found fully serviceable for reasonshereinabove given. Indeed, there is an advantage in stufling the bagsfull in the filling step, since when the walls are completely supportedby the contents, puncturing occurs less readily.

It will be evident that my invention is not limited to any particularform of bag'or seam construction, nor to the specific fabric hereindisclosed, excepting where such features are speciiically set forth inthe appended claims; and that modiiications may be made in my inventionwithout departing from the spirit thereof.

Having thus described my invention, what I 'claim as new and desire tosecure by Letters said layers being in intimate contact with eachvother.

2. Aiplurai ply, flemme bag or like container, all elements of which arecapable of giving. or stretching bodily in opposite directions along theaxes of said container, said container comprising a plurality of layersof universally stretchable substance, at least one layer of which is alayer characterized by universal stretchability derived from gatheringstherein, and at least one layer of which perates to retard thedistention of said like container,

gatherings in said ilrst mentioned layer, all of said layers being inintimate contact with each other, at least two of said layers being inadhesive union with each other.

3. A plural ply, iiexible bag or like container, all plies of whichconsist of elements characterized by universal stretchability, and whichcomprises a plurality of layers of paper in which the universalstretchability is derived from gatherings, all plies of said con'tainerbeing in intimate contact with each other.

4. A plural ply, flexible bag or like container, all plies of whichconsist of elements characterized by universal stretchability, and whichcomprises a plurality of layers of paper in which the universalstretchability is derived from gatherings, all plies of said containerbeing in intimate contact With each other, and certain of said plies atleast being joined by means of a stretchable adhesive.

5. An expansible container consisting of elements all of which arecapable of giving or stretching bodily in opposite directions along theaxes of said container, and comprising a plurality of layers of gatheredmaterial in intimate contact with each other.

ments all of which are capable of giving or stretching bodily inopposite directions along the axes of said container, and comprising aplurality of layers of gathered material joined by means of astretchable adhesive.

'7. A plural ply, exible bag or like container, all elements of whichare capable of giving or stretching bodily in yopposite directions alongthe axes of said container, said container comprising a plurality oflayers of universally stretchable substance, a plurality of said layerscharacterized by universal stretchability derived from gatheringstherein, and at least one universally stretchable layer of whichoperates to retard the distention of said gatherings in one of saidilrst mentioned layers, and is in adhesive union therewith, all of saidlayers being in intimate contact with each other.

8. A plural ply, ilexible bag, or like container, all elements of whichare capable of giving or stretching in both opposite directions alongthe axes of said container, said container comprising a plurality oflayers of universally stretchable substance, a plurality of the layerscharacterized by universal stretchability derived from gatheringstherein, and at least one universally stretchable layer of whichoperates to retard the distention of the gatherings in one of said rstmentioned layers, and all of said universally expansible layers beingjoined by a stretchable adhesive.

9. A plural ply, exible bag or like container, all elements of which arecapable of giving or stretching in both opposite directions along theaxes of said container, said container comprising a plurality of layersof universally stretchable substance, at least one layer of which is alayer characterized by universal stretchability derived from gatheringstherein, and at least one layer of which operates to retard thedistention of said gatherings in said first mentioned layer, said lastmentioned layer comprising heterogeneously arranged and relatively shortbres held in a matrix of stretchable coating substance.

l0. An expansible bag or like container, all elements of which arecapable of giving or stretching in both opposite directions along theaxes of said container, comprising a plurality of layers of paper crepedby means ol a thermoplastic adhesive and characterized by crossing setsof creping crinkles.

11. A bag or like' container, all elements of which are capable ofgiving or stretching in both opposite directions along the axes of saidcontainer, comprising a plurality of plies of -universally stretchablepaper joined together by means of a stretchable adhesive, said containerhaving seams characterized by lapping and adhesive juncture of the bodymaterials as such.

12. An expansible bag or like container, all elements of which arecapable of giving or stretching in both opposite directions along theaxes of said container, comprising walls of universally stretchablepaper joined together by means oi' a stretch- `able adhesive, said wallsbeing substantially co- .terminous at an edge of said bag and lapped inthe marginal portion or a binding strip.

13. A plural ply, flexible bag or like container, all elements of whichare capable of giving or stretching in both opposite directions alongthe 'axes'of said container, said container comprising a plurality oi'layers of universally stretchable substance, at least one layer of whichis a layer characterized by universal stretchability derived fromgatherings therein, and at least one layer oi' which operates to retardthe distention o! said gatherings in said rst mentioned layer, all ofsaid layers being in adhesive union, said container having seams inwhich an edge portion is bodily lapped by and adhesively joined toanother seam forming element.

14. An expansible container, all elements of which are capable of givingor stretching in both opposite directions along the axes of saidcontainer, comprising a plurality of layers of material in adhesiveunion, at least one oi' which layers derives its expansibility fromgatherings therein.

15. An expansible container, all elements of which are capable of givingor stretching bodily in both opposite directions along the axes o1' saidcontainer, comprising a plurality of layers of material in intimatecontact with each other, at

least one oi.' which layers derives its expansibility from gatheringstherein. y

16. An expansible bag or like container, all elements of which arecapable oi' giving or stretching in both opposite directions along theaxes of said container, comprising a plurality of layers oi' material inadhesive union, at least one of which layers derives its expansibilityfrom gatherings therein, and at least one of which layers operates toretard the expansibility of another layer.

WILLIAM WALLACE ROWE.

